-28- 49 of 54 comparisons the scorched leaves contained the highest levels of radioactivity. The chi-square test shows that this difference is highly significant. Since the scorched leaves were unable to absorb nutrients by metabolic means they must have accumulated the radioactive material by physical adsorption. A Similar test showed that the internal portion of the stem contained the lowest amounts of beta radioactivity, which is not surprising, because the internal portion of the stem is the only tissue sampled in which there would be no nation. surface contami- No marked differences in levels of radioactivity were noted among the other six tissues, Comparisons of the relative amounts of beta radioactivity among the tissues of plant species collected at (Table 4) Belle Island trate growth habit, Boerhaavia, grass showed that the plants with a pros- such as that found in Triumfetta and and the forms with limited growth, (Lepturus) and the purslane (Portulaca), such as the contained higher levels of radioactivity than the plants with a taller growth habit, such as Scaevola and Messerschmidia. With increased time after the Nectar test the levels of radioactivity of the different plant parts declined at